Detection of colorectal cancer and adenomas by FDG-PET cancer screening program: results based on a nationwide Japanese survey.

Purpose: The aim of this study was to analyze the detection rate for CRC and adenomas for asymptomatic subjects in Japan by FDG-PET cancer screening program carried out between 2006 and 2009.

Methods: The "FDG-PET cancer screening program" included both PET and positron emission tomography with computed tomography (PET/CT) with or without other screening tests. A total of 154,783 asymptomatic subjects underwent FDG-PET cancer screening program; we analyzed the 1,808 cases with findings from any detection method that indicated suspected CRC.

Results: Among the 1,808 cases, the number of cases verified as CRC and adenoma was 394 and 679, respectively. The sensitivity and positive predictive value (PPV) of FDG-PET were 86.0 and 31.7% for CRC, and 63.6 and 63.8% for CRC and adenoma. The sensitivity and PPV of fecal occult blood test (FOBT) for CRC were lower than those of FDG-PET, but higher for adenoma. Therefore, FDG-PET and FOBT were complementary for screening for CRC, and CRC and adenoma. The majority of CRC detected by the FDG-PET imaging was UICC stage 0 or I, however, detection of smaller or less invasive cancer was limited.

Conclusion: The FDG-PET screening program in Japan has detected CRC at an early stage and adenomas as premalignant lesions. A combination of FDG-PET and FOBT yields the best results if the intent is to detect either CRC or adenoma. However, it is absolutely clear that an FDG-PET cancer screening program cannot detect all colon lesions.